Pseudochactidae Gromov, 1998

Soleglad, Michael E. & Fet, Victor, 2003, High-level systematics and phylogeny of the extant scorpions (Scorpiones: Orthosterni), Euscorpius 2003 (11), pp. 1-175 : 89

Family Pseudochactidae Gromov, 1998 .

Type Genus. Pseudochactas Gromov, 1998 .

Composition. This monotypic family includes a single monotypic genus Pseudochactas (Gromov, 1998; Fet, 2000f).

Distribution. Central Asia (southeastern Uzbekistan, southwestern Tajikistan).

Biogeographic history. Unclear. The single genus Pseudochactas is found only in a restricted location in the mountains of Central Asia. The relict character of Pseudochactas could be due to its preservation in mildclimate, low-mountain depressions of Babatag and Gandzhino ranges (Gromov, 1998), with desert surroundings at lower altitudes. Ecologically, this is not a desert scorpion; it actively forages on wet mud along the temporary waterways, and likely spends most of dry season in hibernation (V. Fet & A. Gromov, pers. observation, 2002). It could represent one of the few faunal remnants of littoral fauna of the receded Tethys Ocean (Kryzhanovsky, 1965), elevated by Tertiary mountain uplift. Many such important floral elements of littoral origin are found in low mountains of Uzbekistan and Tajikistan (Kamelin, 1979).

Diagnosis. As in parvorder Pseudochactida .

Discussion. Gromov (1998: 1003) keenly observed that “It is possible that the representative of this new family ( Pseudochactidae ) stands close to the common ancestor of all these families [the Recent scorpions]”. As Soleglad & Fet (2001) demonstrated based on trichobothrial patterns, Pseudochactas is certainly a basal member of Recent scorpions, and also shows significant affinity in some characters with the Carboniferous fossil scorpion family Palaeopisthacanthidae . This veritable “platypus of a scorpion” deserves further study in all aspects.